Comet Machholz
Background Reading: Stars & Planets pp. 379-381; your ASTR 110 text about comets.
Background
Comet Machholz is a rare object, being just visible with the unaided eye
and well positioned for us to observe it during the spring term. It should
be visible with your binoculars throughout much of January and February,
and with telescopes all term. This comet was only discovered (by Don Machholz
of Colfax, CA) last summer when it was about magnitude 11. It doesn't get
very close to the sun (its orbit keeps it further away from the Sun than
the Earth). Machholz's closest approach to the Sun is on Jan. 24 when it
is 1.2 AU. January 7 it was closest to Earth (at 0.3 AU). To see it look to
the north. It is very close to eta Persei on Jan 25 and is heading down,
towards Polaris.
Objective
On as many nights as possible I'd like you to mark on a sky chart where
you see the comet. In your log include a sketch of anything you see with
your binoculars or the telescope.
From comparison to nearby stars try to estimate the
brightness of the comet in magnitudes. Make at least four observations
of the comet, and try to get about two a week. The first two weeks will be
easier because the moon won't be out and the comet is starting to get
farther away and fainter---so start soon. This project is appropriate
for binoculars, though you may want to take a look through the 8"
telescopes too.
A sky chart centered on Cassiopeia is given below; this covers the range
of the comet path expected through February.
The position of Machholz on Jan 25 is marked, near gamma and eta Persei.
I've also marked a few
"deep-sky" objects on the chart. Try to find M31, the Andromeda
Galaxy. It's visible with the naked eye if the sky is reasonably dark.
Also you may be able to see the Perseus Double Cluster, a pair of star
clusters quite near the present location of Machholz. These and other
objects are described in Stars&Planets under the appropriate
constellation heading.
Report
Keep a log of your observing sessions for this project. At each attempt,
note the date, time, weather and sky conditions, your success at observing
the comet and any objects observed. Carefully mark the comet position on
the sky chart at each observation. Submit a copy of the observing log
together with the sky chart in your report.
Donald L. Mickey
(mickey@ifa.hawaii.edu)
Last modified: January 25, 2005
http://www.ifa.hawaii.edu/users/mickey/ASTR110L_S05/Machholz.html